Vehicles may be equipped with bumper assemblies and impact protection structures that elastically and plastically deform to absorb energy in the event of an impact. Vehicles may also include various protective features that protect vehicle components from environmental conditions, such as water and salt, and road debris. For example, many vehicles include an undercover that protects a vehicle engine and/or other components from beneath the vehicle. Given the location of many engine compartments at a front of the vehicles, the undercover may also be located at the front of the vehicles. Because the undercovers may be located at the front of the vehicles, the undercovers may have some influence on front impact test results, particularly pedestrian leg impact tests. Accordingly, undercover assemblies are desired that can improve pedestrian leg impact test results.